Heat-stable plasticized aminotriazine resin compositions



Patented July 10, 1951 HEAT-STABLE PLASTICIZED AMING- TRIAZINE RESINCOMPOSITIONS Herbert 5. West, Pittsburgh, Pa., and Henry M.

Enter-line, Riverside, Conn, assignors to American Cyanamid Compacorporation of Maine No Drawing.

1945, Serial No.

ny, New York, N. Y., a

Original application January 4,

571,368, new

Patent No.

2,437,657, March 9, 1948. Divided and this application September 10,1947,5erial No. 773,316

1 Claim.

This invention relates to plasticizing amino plastic resins such asurea-aldehyde resins, aminotriazine-aldehyde resins, thiourea-aldehyderesins, dicyandiamide-aldehyde resins, etc.

Alkyd resins modified with fatty oils have been used as plasticizers foramino resins but in each instance there is a tendency to discolor if thecompositions are heated at relatively high temperatures such as forexample in the baking of coating compositions containingsuch materials.The compositions which have been used previously were customarilymodified with fatty acids having relatively long hydrocarbon chains, e.g. 18 carbon atoms. The mixed fatty acids contained in the naturalglyceride, such as coconut oil have been used either as such or inpartially purified form. However, it has been found that even with thehighest grades of refined coconut oil acids enamels containing alkydresins prepared from such acids discolor upon baking,

An object of this invention is to provide resinous plasticizers forvarious amino resins of the type mentioned which are highly resistant todiscoloration upon heating at elevated temperatures.

This and other objects are attained by the use of an alkyd resinmodified with a saturated monocarboxylic acidcontaining from 6 to 10carbon atoms but with no aliphatic acid containing more than 10 carbonatoms andno aliphatic unsaturated acid as a plasticizer for any of thevarious amino resins. Our new plasticizers are particularly suitable foruse in coating compositions containing a urea-formaldehyde resin, anaminotriazine-formaldehyde resin, e. g., a melamineformaldehyderesin,etc. The amino resins used in coating compositions are generallyof the alkylated type such as butylated urea-formaldehyde resins,butylated melamine-formaldehyde resins, etc.

The following examples in which the proportions are in parts by weightare given by way of illustration and not in limitation.

Example 1 148 parts of phthalic anhydride 100 parts of glycerine 110parts of capric acid (CQHIQCOOH) These substances are heated at about220 C. until a resin having an acid number of about 4 is obtained,generally requiring about 6-10 hours.

About 1 part of the product thus produced is mixed with about 1 part(solids basis) of butylated urea-formaldehyde resin (dissolved in butylalcohol and diluted with xylene or other suitable organic solvents ordiluents). The resulting mixture is applied as a coating to variousmaterials such as steel objects. The composition is dried and baked at atemperature of about 250-300" F. A light colored coating which does notdiscolor appreciably during the baking i obtained. The coating has goodflexibility and excellent adhesion to the metal. Similar results areobtained if a butylated melamine-formaldehyde resin be plasticized withthe capric'acid modified glyceride resin. Of course, themelamine-formaldehyde resin compositions are inherently more lightstable and more chemically resistant than the ureaformaldehyde resin. Inmany instances it may be desirable to use mixedmelamine-urea-formaldehyde resins and our plasticizers are also quitesuitable for such materials.

Example 2 148 parts of phthalic anhydride parts of glycerine parts ofZ-ethyl hexoic acid of the capric or 2-ethy1 hexoic acids used in theabove examples, e. g. caproic acid, caprylic acid,

heptoic acid, pelargonic acid, etc. Obviously various mixtures includingtwo, three, four 01' more of any of these acids may be used ifdesirable. The hydroxy aliphatic acids, containing 6-10 carbon atoms, e.g. w-hydroxy decanoic acid, may be used in place of part or all of thenonhydroxylated fatty acids.

Various polyhydric alcohols may be substituted for all or part of theglycerine used in the above examples, e. g. ethylene glycol, di-, tri-,tetra-,

Again there is no penta-, hexa-, octa-ethylene glycols, decamethyleneglycol, 1,3-butylene glycol, a-propylene glycol, octadecanediol, etc.The resins may also be modified if desired with small proportions ofmonohydric alcohols.

Other dicarboxylic acids or the corresponding anhydride may besubstituted for part or all of the phthalic anhydride, e. g. succinic,adipic, sebacic, azelaic, maleic, fumaric, terephthalic acids,endo-methylene tetraphthalic anhydride etc. The term acid as used hereinis intended to include the acid anhydride as well as the acid itself.

The proportion of our plasticizer may be varied considerably. For bestresults it is preferable that about to 4 parts of plasticizer be usedper part of the amino plastic resin.

Various dyes or pigment may be incorporated in the compositionscontaining an amino resin and a plasticizer of the type describedherein. Examples of these are: titanium oxide, ferric oxide, Prussianblue, toluidine red, chrome green, chrome yellow, etc.

If desirable, acid or basic catalysts, e. g. phosphoric acid, may beincluded in the compositions in order to harden the amino resin morerapidly in accordance with principle known in the art.

Plasticizers such as dibutyl phthalate and other alkyl esters phosphate,toluene sulfonamid etc., may also be included in the compositionsdescribed above if desirable.

Among the resins which may be plasticized with the alkyd resinsdescribed herein are those obtained by reacting an aldehyde, (-3. g.formaldehyde, polymers of formaldehyde, acetaldehyde, benzaldehyde,etc., with one or more of the following: urea, thiourea, dicyandiamide,guanidine, heating and decomposing dicyandiamide, aminotriazines such asmelamine, etc. Phenol and the substituted phenols such as the alkylphenols may be included with any of the various'amino compounds justmentioned. Mixed resins such as urea-melamine-formaldehyde resins,urea-thieurea-formaldehyde resins, etc., may be prepared by reacting thealdehyde with each of the other reactants separately and mixing theresulting products or the aldehyde may be reacted with a mixture of theother reactants.

In the production of urea-formaldehyde resins it is preferable that theformaldehyde to urea ratio be between about 2:1 and 3:1 whereas in thepreparation of melamine-formaldehyde-resins it is preferable that theformaldehyde to melamine ratio be between about 3:1 and 6:1. Higher orlower ratios may of course also be employed.

These amino resins are preferably alkylated with a suitable alcohol, e.g. ethanol, propanol, butanol, amyl alcohol, cyclohexanol, benzylalcohol, etc. To prepare alkylated amino resins, the amino compound suchas urea is generally condensed with an aqueous solution of formaldehydeand the alcohol which is to be used for phthalic acid, sodium carbonate,etc.

of phthalic acid, tricresyl the reaction products obtained by alkylationis added to the resulting aqueous syrup. The mixture is thenazeotropically distilled and the water is separated by means of asuitable water trap. Usually the alkylated resins are dissolved in, ordiluted with, organic solvents such as the alcohols just mentioned,xylene, toluol, etc.

Coating composiitons containing our new plasticizers together with anamino resin when used with light colored pigments are especiallysuitable as regfrigerator enamels, stove enamels, medicine cabinetenamels, etc. The non-pigmented compositions are suitable for use asclear lacquers on metal, wood, etc. Composi- F tions containing an aminoresin and our plasticizers are also of value with dark pigments althoughcolor changes are not so apparent when dark pigments are used.

Our plasticizers appear to be substantially stable against discolorationwhen heated at temperatures up to about 450 F. for relatively longperiods of time. On the other hand alkyd resin plasticizers containinglong chain fatty acids discolor quite rapidly when heated attemperatures of about 450 E. for similar periods of time.

This application is a continuation-in-part of our abandoned copendingapplication Serial No. 329,056, filed April 11, 1940 and a divisional ofour application Serial No. 571,368, filed January 4, 1945, now PatentNo. 2,437,657, March 9, 1948.

Obviously many modificationsand variations in the processes andcompositions described above may be made without departing from thespirit and scope of the invention a defined in the appended claim.

We claim:

A resinous butylated melamine-formaldehyde condensation product which isa reaction product of melamine, formaldehyde and a butyl alcoholplasticized with a resinous reaction product of phthalic acid, glyceroland 2-ethyl hexoic acid.

HERBERT J. WEST. HENRY M. ENTERLINE.

REFERENCES CITED The following references are of record inthe file ofthis patent:

UNITED STATES PATENTS OTHER REFERENCES Lewkowitsch Chemical Technologyand Analysis of Oils, Fats and Waxes, 6th ed., Vol.11, pages 655 and656.

